Electrically-conductive article with improved bus region

ABSTRACT

Electrically-conductive articles are prepared to have electrically-conductive silver metal electrode grids and electrically-conductive silver connector wire patterns (BUS lines) on one or both supporting sides of a transparent substrate. The electrically-conductive silver connector wire patterns are designed with at least one silver main wire that comprises two or more adjacent silver micro-wires in bundled patterns. These bundled patterns and silver micro-wires are designed with specific dimensions and configurations to provide optimal fidelity (or correspondence) to the mask image used to provide such images in a silver halide emulsion layer. The electrically-conductive articles are provided by imagewise exposure, development, and fixing of corresponding silver halide-containing conductive film element precursors containing photosensitive silver halide emulsion layers. The electrically-conductive articles can be used are parts of various electronic devices including touch screen devices.

RELATED APPLICATIONS

Reference is made to the following copending and commonly assignedpatent applications, the disclosures of all of which are incorporatedherein by reference:

U.S. Ser. No. 13/751,430 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok);

U.S. Ser. No. 13/751,443 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok), now issued as U.S. Pat. No. 9,167,688 on Oct. 20, 2015;

U.S. Ser. No. 13/751,464 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok), now issued as U.S. Pat. No. 9,005,744 on Apr. 14, 2015;

U.S. Ser. No. 13/751,450 (filed Jan. 28, 2013 by Lebens, Trauernicht,Wang, and Cok), now issued as U.S. Pat. No. 9,137,893 on Sep. 15, 2015;

U.S. Ser. No. 13/964,453 (filed Aug. 12, 2013 by Lebens and Cok), nowissued as U.S. Pat. No. 9,131,606 on Sep. 8, 2015;

U.S. Ser. No. 14/166,910 (filed Jan. 29, 2014 by Kenneth Lushington),now issued as U.S. Pat. No. 9,247,640 on Jan. 26, 2016;

U.S. Ser. No. 14/281,925 (filed on May 20, 2014, by Lushington, Sutton,and Cok, and issued as U.S. Pat. No. 9,235,130 on Jan. 12, 2016)entitled “Method for Preparing Transparent Electrically-ConductiveArticles;”

U.S. Ser. No. 14/281,923 (filed on May 20, 2014, by Lushington, Cok, andSutton, and published as U.S. 2015/0338969 on Nov. 26, 2015) entitled“Article with Electrically Conductive Silver Connector Wire Pattern;”

U.S. Ser. No. 14/281,968 (filed on May 20, 2014 by Youngblood and Lowe,and published as U.S. 2015/0338740 on Nov. 26, 2015) entitled “Methodfor Providing Conductive Silver Film Elements;”

U.S. Ser. No. 14/281,977 (filed on May 20, 2014, by Youngblood and Lowe,and published as U.S. 2015/0338741 on Nov. 26, 2015) entitled “SilverHalide Developing Solution;”and

U.S. Ser. No. 14/281,984 (filed on May 20, 2014, by Youngblood and Lowe,and published as U.S. 2015/0338742 on Nov. 26, 2015) entitled “SilverHalide Solution Physical Developing Solution.”

FIELD OF THE INVENTION

This invention relates to generally transparent electrically-conductivearticles having electrically-conductive silver electrode grids andelectrically-conductive silver connector wire patterns, whichelectrically-conductive articles are prepared from conductive filmelement precursors that have a photosensitive silver halide emulsionlayer on one or both sides of a transparent substrate. Theelectrically-conductive articles have specifically arrangedelectrically-conductive silver metal (fine wire) grids in a touch regionand electrically-conductive silver connector wire patterns on one orboth sides of the transparent substrate. This invention also relates todevices such as touch screen panels into which theseelectrically-conductive articles can be incorporated.

BACKGROUND OF THE INVENTION

Rapid advances are occurring in various electronic devices especiallydisplay devices that are used for various communicational, financial,and archival purposes. For such uses as touch screen panels,electrochromic devices, light-emitting diodes, field-effect transistors,and liquid-crystal displays, electrically-conductive films are essentialand considerable efforts are being made in the industry to improve theproperties of those conductive films and particularly to improve metalgrid or line conductivity and to provide as much correspondence betweenmask design with resulting user metal patterns.

Electrically-conductive articles used in various electronic devicesincluding touch screens in electronic, optical, sensory, and diagnosticdevices including but not limited to telephones, computing devices, andother display devices have been designed to respond to touch by a humanfingertip or mechanical stylus.

There is a particular need to provide touch screen displays and devicesthat contain improved conductive film elements. Currently, touch screendisplays use Indium Tin Oxide (ITO) coatings to create arrays ofcapacitive areas used to distinguish multiple points of contacts. ITOcoatings have significant disadvantages and efforts are being made toreplace their use in various electronic devices.

Silver is an ideal conductor having an electrical conductivity 50 to 100times greater than ITO and is being explored for this purpose. Unlikemost metal oxides, silver oxide is still reasonablyelectrically-conductive and this reduces the problem of making reliableelectrical connections. Silver is used in many commercial applicationsand is available from numerous sources. It is highly desirable to makeelectrically-conductive film elements using silver as the source ofconductivity, but it requires considerable development to obtain optimalproperties.

In known printed circuit board (PCB) and integrated circuit manufactureprocesses, the preferred means for mass manufacture is to print acircuit directly from a master article onto a suitable substrate, tocreate a copy of the circuit image on a suitable PCB photosensitivefilm, or to directly laser-write a master circuit image (or inversepattern) onto the PCB photosensitive film. The imaged PCB photosensitivefilm is then used as a “mask” for imaging multiple copies onto one ormore photoresist-coated substrates.

An essential feature of these methods is that the PCB photosensitivefilm and photoresist compositions are optimized in formulation anddevelopment so that the imaged copies are as faithful a representationof the master image as possible with respect to circuit dimensions andproperties. This property is sometimes referred to as “fidelity” (or“correspondence”) and the worse the fidelity, the poorer the performanceof the resulting copies. However, in mass production of these electricalcircuits having designed patterns with very fine dimensional features,there are a number of compositional and operational (for example,chemical processing) conditions that naturally work against fidelity, ormaking faithful reproductions of the master circuit image.

This is particularly true when silver halide is used for making themultiple copies of a master circuit pattern intended for use astransparent conductor patterns. For example, development of exposedsilver halide using strong developers intended to achieve highconductivity, and the high level of silver in the photosensitivecoatings for the same purpose, can lead to very large dimensionaldifferences between the master circuit image and copies made thereofusing various mask elements. In addition, this lack of faithfulreproduction of the dimensions in the master circuit image is stronglyinfluenced by the dimensional scale of the circuitry images that arebeing reproduced. Thus, smaller features in the master circuit imagebecome larger and the larger features in the master circuit image becomesmaller. These objectionable changes in the features from “master tocopy” result in reduced conductivity in the resulting copy patterns andoverall poorer performance in the electrical devices in which they areincorporated.

It requires considerable research and development effort to determinethe various causes of the lack of fidelity between master circuit imageand copies, especially when photosensitive silver halide is used forthis process. There are numerous publications relating to usingphotosensitive silver halide in this manner, but none that addresses thenoted problem.

For example, U.S. Patent Application Publication 2011/0308846 (Ichiki)describes the preparation of electrically-conductive films formed byreducing a silver halide image in electrically-conductive networks withsilver wire sizes less than 10 μm, which electrically-conductive filmscan be used to form touch panels in displays. In addition, improvementshave been proposed for providing electrically-conductive patterns usingphotosensitive silver salt compositions such as silver halide emulsionsas described for example in U.S. Pat. No. 8,012,676 (Yoshiki et al.).

Recently designed improved electrically-conductive articles are preparedfrom photosensitive silver halide precursor articles as described forexample in copending and commonly assigned U.S. Ser. No. 14/166,910(noted above).

Electrically-conductive silver articles have been described for use intouch screen panels that have electrically-conductive silver gridpatterns on both sides of a transparent substrate, for example as inU.S. Patent Application Publications 2011/0289771 (Kuriki) and2011/0308846 (Ichiki).

However, the mere presence of electrically-conductive silver gridpatterns on one or both sides of the transparent substrate is notsufficient to provide sufficient response that is needed for sensingtouch for various electronic devices. The electrically-conductive gridpatterns must be connected in some manner to each other and to suitableelectronic components and software in the devices so that desiredfunctions can be accomplished in response to a touch from a finger orstylus. Thus, the electrically-conductive articles are also designedwith conductive “BUS” lines or conductive silver connecting wiring thatis outside the electrically-conductive electrode regions (“touchregions”) designed for touching. In some embodiments, suchelectrically-conductive articles have “sensitive regions” and “terminalwiring regions” on one or both sides of the transparent substrate. Onerepresentation of such an electrically-conductive article is shown inFIG. 8 of U.S. Patent Application 2011/0289771 (noted above).

Normally, the electrically-conductive wiring in theelectrically-conductive article is not designed for high transparency orsensitivity to touch. The electrically-conductive wiring will likelyhave different conductivity and dimensions compared to the conductivegrid patterns in what are known as the “sensitive regions” of theelectrically-conductive article. These differences further make itharder to achieve desired fidelity of a master circuit image and copiesmade therefrom.

Thus, there is a need for a means for providing transparentelectrically-conductive articles that have both electrically-conductivesilver grids in touch sensitive regions as well aselectrically-conductive silver wiring that are as close to beingreproductions to the master circuit image as possible. The presentinvention addresses these problems.

SUMMARY OF THE INVENTION

The present invention addresses these problems by providing anelectrically-conductive article using photosensitive silver halide. Thiselectrically-conductive article comprises a transparent substrate havinga first supporting side and an opposing second supporting side,

the first supporting side comprising: (a) an electrically-conductivesilver metal electrode grid, (b) an electrically-conductive silverconnector wire pattern, and optionally, (c) transparent regions outsideof both the electrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern,

wherein:

(i) the electrically-conductive silver connector wire pattern comprisesat least one silver main wire that comprises two or more silvermicro-wires that are electrically connected to a silver end wire at anend of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between any two adjacent silver micro-wires in eachbundled pattern is at least 0.5:1 but less than 2:1; and

(iv) the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 68%.

Such embodiments can further comprise on the opposing second supportingside of the transparent substrate: (a) an opposingelectrically-conductive silver metal electrode grid, (b) an opposingelectrically-conductive silver connector wire pattern, and optionally,(c) transparent regions outside of both the opposingelectrically-conductive silver metal electrode grid and the opposingelectrically-conductive silver connector wire pattern,

wherein, on the opposing second supporting side of the transparentsubstrate:

(i) the opposing electrically-conductive silver connector wire patterncomprises at least one silver main wire that comprises two or moresilver micro-wires that are electrically connected to a silver end wireat an end of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 0.5:1 but less than 2:1; and

(iv) the opposing electrically-conductive silver connector wire patternhas an integrated transmittance of less than 68%.

Still other useful embodiments comprise an electrically-conductivearticle comprising a transparent substrate having a first supportingside and an opposing second supporting side,

the first supporting side comprising: (a) an electrically-conductivesilver metal electrode grid, (b) an electrically-conductive silverconnector micro-wire pattern comprising at least one silver micro-wire,and optionally, (c) transparent regions outside of both theelectrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern,

wherein the ratio of maximum height to minimum height of the at leastone silver micro-wire is at least 1.05:1.

Such embodiments can further comprise on the opposing second supportingside of the transparent substrate: (a) an opposingelectrically-conductive silver metal electrode grid, (b) an opposingelectrically-conductive silver connector wire pattern, and optionally,(c) transparent regions outside of both the opposingelectrically-conductive silver metal electrode grid and the opposingelectrically-conductive silver connector wire pattern,

wherein the ratio of maximum height to minimum height of the at leastone silver micro-wire on the opposing second supporting side of thetransparent substrate is at least 1.05:1.

The electrically-conductive articles of this invention are providedusing photosensitive black-and-white silver halide emulsions andblack-and-white silver halide processing chemistry in a method describedin detail below.

Thus, the method described herein provides an electrically-conductivearticle that has both electrically-conductive silver metal electrodegrids (for the “touch sensitive” or “touch” regions) andelectrically-conductive silver connector wire patterns (also identifiedas BUS lines, BUS regions, or simply electrode wire connector regions)with improved matching (correspondence or fidelity) of the images ofthese regions to the images in the original mask element through whichimagewise exposure occurs.

The advantages are achieved for the electrically-conductive silverconnector wire patterns in the electrode wire connector regions byarranging at least one silver main wire (for example, two or more silvermain wires) into bundled patterns of two or more silver micro-wires andvarious silver end wires for each bundled pattern. In addition, adjacentsilver micro-wires in the bundled pattern can be arranged with bothelectrically connecting silver cross-wires and silver end wires. Thebundled patterns and silver micro-wires are obtained from exposure andprocessing with specific dimensions, spacing, and conductive propertiesfor optimal performance in touch screen devices. The bundled patterns ofsilver main wires and silver micro-wires increase electricalconductivity, manufacturability, and robustness even in the presence ofsome manufacturing defects. In other words, the possible effects ofmanufacturing defects or inconsistencies are at least reduced in theelectrically-conductive articles of the present invention.

Known methods for preparing electrically-conductive articles typicallycause the formation of continuous, solid, and substantially flatconductive lines and attempt to make maximum use of the available spaceon a transparent substrate. However, it has been found that the use ofsolution physical development with imagewise exposed silver halideemulsions does not readily allow the formation of such continuous,solid, and substantially flat conductive lines having desired electricalconductivity and lower resistance. Hence, known silver halide films andprocessing methods are not useful for this purpose, and would not teachor motivate a skilled worker to find and use the electrically-conductivearticle of the present invention. In particular, methods of the art thatinclude silver halide development but do not include solution physicaldevelopment, or which include known plating methods in which thedeposited metals (or metal ions) come from an external source such as asolution, can form continuous, solid, and flat conductive lines andtherefore do not suggest the electrically-conductive articles of thepresent invention.

In contrast to known methods, the electrically-conductive articles ofthe present invention exhibit improved electrical conductivity from thepresence of unique silver micro-wire bundled patterns. In one usefulembodiment, the silver-micro-wires have an average width of at least 5μm and up to and including 20 μm. Thus, the method described hereinprovides electrically-conductive articles having highlyelectrically-conductive silver connector wire patterns without requiringthe formation of continuous, solid, and substantially flat conductivelines.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an electrically-conductive silverconnector wire pattern shown on one side of a transparent substrate,which electrically-conductive connector silver wire pattern can beincorporated into or part of an electrically-conductive article of thisinvention.

FIG. 2 is a schematic cross-sectional view of an electrically-conductivearticle according to the present invention.

FIG. 3A is a schematic cross-sectional view of a conductive film elementprecursor comprising a portion of a photosensitive silver halideemulsion layer disposed on a transparent substrate, which portion ofphotosensitive silver halide emulsion layer comprises non-developedphotosensitive silver halide grains.

FIG. 3B is a schematic cross-sectional view of a conductive film elementprecursor comprising developed photosensitive silver halide grains in arepresentative silver micro-wire disposed on a transparent substrate,which silver micro-wire can be obtained from the portion ofphotosensitive silver halide emulsion layer shown in FIG. 3A.

FIGS. 4 and 5 are schematic illustrations of electrically-conductivesilver connector wire patterns shown on one side of a transparentsubstrate, showing both silver end wires and different arrangements ofsilver cross-wires in multiple bundled patterns.

FIGS. 6 to 9 are flow charts showing options for formingelectrically-conductive articles from single-sided or duplex conductivefilm element precursors.

FIG. 10 is a schematic cross-sectional view of a silver micro-wire on atransparent substrate, which silver micro-wire has a maximum heightessentially at its center.

FIG. 11 is a schematic cross-sectional view of a silver micro-wire on atransparent substrate, which silver micro-wire has a maximum heightcloser to its outer edge than its center.

DETAILED DESCRIPTION OF THE INVENTION

The following discussion is directed to various embodiments of thepresent invention and while some embodiments can be more desirable forspecific uses, the disclosed embodiments should not be interpreted orotherwise considered to be limiting the scope of the present invention,as claimed below. Thus, one skilled in the art should understand thatthe following disclosure and illustrative FIGS. have broader applicationthan is explicitly described and the discussion or illustration of anembodiment is not intended to limit the scope of the present invention.

Definitions

As used herein to define various components and structures of theconductive film element precursors including photosensitive silverhalide emulsion layers and processing solutions, unless otherwiseindicated, the singular forms “a”, “an”, and “the” are intended toinclude one or more of the components (that is, including pluralityreferents).

Each term that is not explicitly defined in the present application isto be understood to have a meaning that is commonly accepted by thoseskilled in the art. If the construction of a term would render itmeaningless or essentially meaningless in its context, the termdefinition should be taken from a standard dictionary.

The use of numerical values in the various ranges specified herein,unless otherwise expressly indicated otherwise, are considered to beapproximations as though the minimum and maximum values within thestated ranges were both preceded by the word “about”. In this manner,slight variations above and below the stated ranges can be used toachieve substantially the same results as the values within the ranges.In addition, the disclosure of these ranges is intended as a continuousrange including every value between the minimum and maximum values.

Unless otherwise indicated, the term “weight %” refers to the amount ofa component or material based on the total solids of a composition,formulation, solution, or the % of the dry weight of a layer. Unlessotherwise indicated, the percentages can be the same for either a drylayer or pattern, or for the total solids of the formulation orcomposition used to make that layer or pattern.

Unless otherwise indicated, the terms “conductive film elementprecursor” and “precursor” are meant to be the same thing and to referto an article used in the practice of the method of this invention toprovide a electrically-conductive film element (orelectrically-conductive article) of the present invention. Suchprecursors therefore comprise a “silver precursor material” (such as asilver halide) that can be converted to conductive silver metalparticles (for example by reduction). Much of the discussion about theprecursors is equally applicable to the electrically-conductive articlesas most of the components and structure are not changed when silvercations are converted to silver metal particles. Thus, unless otherwiseindicated, the discussion of transparent substrates, hydrophilic bindersand colloids, and other addenda in photosensitive silver halide emulsionlayers, any hydrophilic overcoats, and any other components or layersfor the precursors are also intended to describe the components of theresulting electrically-conductive articles.

Unless otherwise indicated, the terms “electrically-conductive filmelement” and “electrically-conductive article” are intended to mean thesame thing. They refer to the materials containing theelectrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns disposed oneither or both supporting sides of a suitable transparent substrate.Other components of the electrically-conductive articles are describedbelow.

The term “first” refers to the layers on one (first) supporting side ofthe transparent substrate and the term “second” refers to the layers onthe opposing (opposite) second supporting side of the transparentsubstrate. Each supporting side of the transparent substrate can beequally useful and the term “first” does not necessarily mean that oneside is the primary or better supporting side of the precursor orelectrically-conductive article.

The terms “duplex” and “two-sided” are used herein in reference toprecursors and electrically-conductive articles having the describedlayers and electrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns on bothsupporting sides of the transparent substrate. Unless otherwiseindicated herein, the relationships and compositions of the variouslayers can be the same or different on both supporting sides of thetransparent substrate.

ESD refers to “equivalent spherical diameter” and is a term used in thephotographic art to define the size of particles such as silver halidegrains. Particle size of silver halide grains as expressed in grain ESDcan be readily determined using disc centrifuge instrumentation.

Unless otherwise indicated, “black-and-white” refers to silver-formingblack-and-white materials and formulations, and not chromogenicblack-and-white materials and formulations.

In most embodiments, the conductive film element precursors and theresulting electrically-conductive articles, including the transparentsubstrate and all accompanying layers, electrically-conductive silvermetal electrode grids, and transparent regions on one or both supportingsides, are considered transparent meaning that its integratedtransmittance over the noted region of the electromagnetic spectrum (forexample from 410 nm to 700 nm) is 70% or more, or more likely at least85% or even 90% or more, as measured for example using aspectrophotometer and known techniques. Thus, the touch regions in theresulting electrically-conductive articles will have this highintegrated transmittance. However, the electrode connector regionscontaining the electrically-conductive silver connector wire patternsare generally much less transparent than the rest of theelectrically-conductive articles and generally have an integratedtransmittance of less than 68%, or less than 50%, or even less than 40%using the same equipment and procedures noted above.

Alternatively, the integrated transmittance can be associated with thecalculated percentage of the transparent substrate area that is notcovered by either the electrically-conductive silver metal electrodegrid in the touch region or by the electrically-conductive silverconnector wire pattern in the electrode connector regions.

In defining various dimensions of the silver main wires and silvermicro-wires provided in the electrically-conductive articles, eachdimension “average” is determined from at least 5 measurements of thespecific dimension using appropriate measurement techniques andequipment that would be known to one skilled in the art.

Unless otherwise indicated, the terms “electrode wire connectorregions”, “BUS lines”, and “BUS regions” mean the same thing.

Uses

The conductive film element precursors can be used to formelectrically-conductive articles that also have various uses. Forexample, the electrically-conductive articles can be used as devicesthemselves or they can be used as components in devices having a varietyof applications including but not limited to, electronic, optical,sensory, and diagnostic uses. In particular, it is desired to use theconductive film element precursors to provide highlyelectrically-conductive silver metal electrode grids andelectrically-conductive silver metal connector wire patterns comprisingsilver metal lines having suitable height, width, and conductivity foruse in touch screen displays or as components of touch-screen devices.Such electronic and optical devices and components include but are notlimited to, radio frequency tags (RFID), sensors, touch-screen displays,and memory and back-panels for displays.

Conductive Film Element Precursors

The conductive film element precursors used in the practice of thisinvention comprise photosensitive silver halide(s) but they do notgenerally contain chemistry sufficient to provide color photographicimages. Thus, these “precursors” are considered to be black-and-whitephotosensitive materials forming metallic silver images followingexposure and development and are non-color image-forming.

The precursors and the resulting electrically-conductive articles,including the transparent substrate and all accompanying layers on oneor both supporting sides, are considered transparent in the touchregions in which the electrically-conductive silver metal electrodegrids are formed, and other transparent regions outside theelectrically-conductive silver metal electrode grids and theelectrically-conductive silver connector wire pattern, meaning that theintegrated transmittance over the visible region of the electromagneticspectrum (for example from 410 nm to 700 nm) through the entireelectrically-conductive article in these touch regions and othertransparent regions is 70% or more, or more likely at least 85%, or even90% or more. Integrated transmittance is measured as described above.

However, the electrode connector regions of the processed photosensitivesilver halide emulsion layers that are used to provide theelectrically-conductive silver connector wire patterns, are lesstransparent due to the higher coverage of silver metal formed in thoseelectrode connector regions. For example, such electrode connectorregions comprised of electrically-conductive silver connector wirepatterns generally have an integrated transmittance of less than 68%, orless than 50%, or even less than 40%.

The precursors can be formed by providing a non-color (that is,silver-forming black-and-white) photosensitive silver halide emulsionlayer on one or both supporting sides (or planar sides as opposed tonon-supporting edges) of a suitable transparent substrate in a suitablemanner. Each photosensitive layer comprises a silver halide, or amixture of silver halides, at a suitable silver coverage, such as atotal silver coverage of at least 2500 mg Ag/m², or at least 3500 mgAg/m² but usually less than 5000 mg Ag/m², for example up to andincluding 4950 mg Ag/m². However, higher amounts of silver coverage canbe used as would be known in the art. Thus, each photosensitive layerhas sufficient silver halide intrinsic or added spectral sensitizationto be photosensitive to preselected imaging irradiation (describedbelow). The photosensitive layers can be the same or different incomposition and spectral sensitization on the opposing supporting sidesof the transparent substrate.

The one or more silver halides are dispersed within one or more suitablehydrophilic binders or colloids as described below.

Such precursors are therefore treated (or processed) in such a manner asto convert the silver cations into silver metal particles (such as byreduction), and this treated precursor can then become anelectrically-conductive article of the present invention.

The precursors can have one essential layer on each supporting side ofthe transparent substrate, which essential layer is a photosensitivesilver halide emulsion layer. This essential layer can be disposed ononly one supporting side of the transparent substrate, but in manyduplex embodiments, it is disposed on both first supporting and opposingsecond supporting sides of the transparent substrate. Optional layers,such as hydrophilic overcoats and filter dye layers can also be presenton either or both supporting sides and are described below but they arenot essential to achieve the desired advantages of the presentinvention.

Transparent Substrates:

The choice of a transparent substrate generally depends upon theintended utility of the resulting electrically-conductive article suchthat the electrically-conductive article can be fabricated in a suitablemanner for a predetermined device. The transparent substrate can berigid or flexible, and generally has an integrated transmittance of atleast 90% and generally at least 95% over the visible region of theelectromagnetic spectrum (for example at least 410 urn and up to andincluding 700 nm). Integrated transmittance can be determined using aspectrophotometer and known procedures as described above.

Suitable transparent substrates include but are not limited to, glass,glass-reinforced epoxy laminates, cellulose triacetate, acrylic esters,polycarbonates, adhesive-coated polymer transparent substrates,polyester films, and transparent composite materials. Suitabletransparent polymers for use as transparent polymer substrates includebut are not limited to, polyethylene and other polyolefins, polyesterssuch as polyethylene terephthalate (PET), polyethylene naphthalate(PEN), poly-1,4-cyclohexanedimethylene terephthalate, poly(butyleneterephthalate), and copolymers thereof, polypropylenes, polyvinylacetates, polyurethanes, polyamides, polyimides, polysulfones,polycarbonates, and mixtures thereof. Other useful transparentsubstrates can be composed of cellulose derivatives such as a celluloseester, cellulose triacetate, cellulose diacetate, cellulose acetatepropionate, cellulose acetate butyrate, polyacrylates, polyether imides,and mixtures thereof.

Transparent polymeric substrates can also comprise two or more layers ofthe same or different polymeric composition so that the compositetransparent substrate (or laminate) has the same or different layerrefractive properties. The transparent substrate can be treated oneither or both supporting sides to improve adhesion of a photosensitivesilver halide emulsion or underlying layer. For example, the transparentsubstrate can be coated with a polymer adhesive layer, chemicallytreated, or subjected to a corona treatment on one or both supportingsides.

Commercially available oriented and non-oriented transparent polymerfilms, such as biaxially-oriented polypropylene or polyester, can beused. Such transparent substrates can contain pigments, air voids orfoam voids as long as desired integrated transmittance is obtained. Thetransparent substrate can also comprise microporous materials such aspolyethylene polymer-containing material sold by PPG Industries, Inc.,Pittsburgh, Pa. under the trade name of Teslin®, Tyvek® synthetic paper(DuPont Corp.). The transparent substrate also can be voided, whichmeans it contains voids formed as interstitial voids using added solidand liquid materials, or “voids” containing a gas. Some commercialmicrovoided products are commercially available as 350K18 fromExxonMobil and KTS-107 (from HSI, South Korea).

Biaxially-oriented sheets, while described as having at least one layer,can also be provided with additional layers that can serve to change theoptical or other properties of the biaxially-oriented sheet. Such layersmight contain tints, antistatic or conductive materials, or slip agents.The biaxially-oriented extrusion can be carried out with as many as 10layers if desired, made with layers of the same polymeric material, orwith layers having different polymeric composition.

Flexible transparent substrates for the manufacture of flexibleelectronic devices or touch screen components facilitate rapidroll-to-roll manufacture. Estar® poly(ethylene terephthalate) films andcellulose triacetate films are particularly useful materials for makingflexible transparent substrates.

The transparent substrate used in the precursors can have a thickness ofat least 20 μm and up to and including 300 μm or typically at least 75μm and up to and including 200 μm. Antioxidants, brightening agents,antistatic or conductive agents, plasticizers, and other known additivescan be incorporated into the transparent substrate, if desired, inamounts that would be readily apparent to one skilled in the art as longas desired integrated transmittance is preserved.

Photosensitive Silver Halide Emulsion Layers:

The essential silver halide(s) in these layers comprise silver cationsof one or more silver halides that can be converted into silver metalparticles according to desired patterns upon imagewise exposure of eachphotosensitive silver halide emulsion layer. Such exposure is generallyachieved by imaging through a mask element that is designed withpredetermined patterns for both the electrically-conductive silver metalelectrode grid and the electrically-conductive silver connector wirepattern. The latent image(s) provided by this exposure can then bedeveloped into desired silver metal image(s) using known silverdevelopment procedures and chemistry (described below). The silverhalide (or combination of silver halides) is photosensitive, meaningthat radiation from UV to visible light (for example, of at least 200 nmand up to and including 750 nm radiation) is generally used to convertsilver cations to silver metal particles in a latent image. In someembodiments, the silver halide is present in combination with athermally-sensitive silver salt (such as silver behenate) and thephotosensitive silver halide emulsion layer can be both photosensitiveand thermally sensitive (that is, sensitive to thermal imaging energysuch as infrared radiation).

The useful photosensitive silver halides can be, for example, silverchloride, silver bromide, silver chlorobromoiodide, silverbromochloroiodide, silver chlorobromide, silver bromochloride, or silverbromoiodide that are prepared as individual compositions (or emulsions).The various halides are listed in the silver halide name in descendingorder of halide amount. In addition, individual silver halide emulsionscan be prepared and mixed to form a mixture of silver halide emulsionsthat are used on the same or different supporting sides of thetransparent substrate. In general, the useful silver halides comprise upto and including 100 mol % of chloride or up to and including 100 mol %of bromide, and up to and including 5 mol % iodide, all based on totalsilver. These silver halides are generally known as “high chloride” or“high bromide” silver halides and can be used to form “high chloride,”or “high bromide” emulsions, respectively.

The silver halide grains used in each photosensitive silver halideemulsion layer generally have an ESD of at least 30 nm and up to andincluding 300 nm, or more likely at least 50 nm and up to and including200 nm.

The coverage of total silver in each photosensitive silver halideemulsion layer is desirably at least 2500 mg Ag/m² and typically atleast 3500 mg Ag/m² and can be less than 5000 mg Ag/m², although higheramounts can be used.

The dry thickness of each photosensitive silver halide emulsion layer isgenerally at least 0.5 μm and up to and including 12 μm, andparticularly at least 0.5 μm and up to and including 7 μm.

The final dry photosensitive silver halide emulsion layer can be made upof one or more individually coated photosensitive silver halide emulsionsub-layers that can be applied using the same or different silver halideemulsion formulations. Each sub-layer can be composed of the same ordifferent silver halide(s), hydrophilic binders or colloids, andaddenda. The photosensitive silver halide emulsion sub-layers can havethe same or different amount of silver content.

The photosensitive silver halide(s) used in the photosensitive silverhalide emulsion layer on the first supporting side can be the same ordifferent from the photosensitive silver halide(s) used in the opposingsecond supporting side photosensitive silver halide emulsion layer.

The photosensitive silver halide grains (and any addenda associatedtherewith as described below) are dispersed (generally uniformly) in oneor more suitable hydrophilic binders or colloids to form a hydrophilicsilver halide emulsion. Examples of such hydrophilic binders or colloidsinclude but are not limited to, gelatin and gelatin derivatives,polyvinyl alcohol (PVA), poly(vinyl pyrrolidone) (PVP), casein, andmixtures thereof. Suitable hydrophilic colloids and vinyl polymers andcopolymers are also described in Section IX of Research Disclosure Item36544, Sep. 1994 that is published by Kenneth Mason Publications,Emsworth, Hants, PO10 7DQ, UK. A particularly useful hydrophilic colloidis gelatin or a gelatin derivative of which several are known in theart.

The amount of hydrophilic binder or colloid in each photosensitivesilver halide emulsion layer can be adapted to the particular drythickness that is desired as well as the amount of silver halide that isincorporated. It can also be adapted to meet desired dispersibility,swelling, and layer adhesion to the transparent substrate. The amount ofhydrophilic binder or colloid is generally controlled to maximize theconductivity of the resulting silver metal particles in theelectrically-conductive articles.

In general, the one or more hydrophilic binders or colloids are presentin an amount of at least 10 weight % and up to and including 95 weight%, or more likely at least 10 weight % and up to and including 50 weight%, all based on the total solids in the dry photosensitive silver halideemulsion layer.

Some useful photosensitive silver halide emulsion layer compositionshave a relatively high silver ion/hydrophilic binder (for example,gelatin) weight (or volume) ratio. For example, a particularly usefulweight ratio of silver ions (and eventually silver metal) to hydrophilicbinder or colloid such as gelatin (or its derivative) is at least 0.1:1,or even at least 1.5:1 and up to and including 10:1. A particularlyuseful weight ratio of silver ions to the hydrophilic binder or colloidcan be at least 2:1 and up to and including 5:1. Other weight ratios canbe readily adapted for a particular use and dry layer thickness.Particularly useful silver ion/hydrophilic binder (gelatin) volume ratiois less than 0.5:1 or even less than 0.35:1.

The hydrophilic binder or colloid can be used in combination with one ormore hardeners designed to harden the particular hydrophilic binder suchas gelatin. Particularly useful hardeners for gelatin and gelatinderivatives include but are not limited to, non-polymeric vinyl-sulfonessuch as bis(vinyl-sulfonyl) methane (BVSM), bis(vinyl-sulfonyl methyl)ether (BVSME), and 1,2-bis(vinyl-sulfonyl acetamide)ethane (BVSAE).Mixtures of hardeners can be used if desired. The hardeners can beincorporated into each photosensitive silver halide emulsion layer inany suitable amount that would be readily apparent to one skilled in theart.

In general, each photosensitive silver halide emulsion layer can behardened so that it has a swell ratio of at least 150% but less than300% as determined by optical microscopy of element cross-sections, andthe swell ratio can be provided by use of appropriate amounts ofhardeners within the photosensitive silver halide emulsion layer, orhardeners within various processing solutions (described below).

If desired, the useful silver halides described above can be sensitizedto any suitable wavelength of exposing radiation. Organic sensitizingdyes can be used, but it can be advantageous to sensitize the silversalt to the UV portion of the electromagnetic spectrum without usingvisible light sensitizing dyes to avoid unwanted dye stains if theelectrically-conductive article containing the silver metal particles isintended to be transparent. Alternatively, the silver halides can beused without spectral sensitization beyond their intrinsic spectralsensitivities.

Non-limiting examples of addenda that can be included with the silverhalides, including chemical and spectral sensitizers, filter dyes,organic solvents, thickeners, dopants, emulsifiers, surfactants,stabilizers, hardeners, and antifoggants are described in ResearchDisclosure Item 36544, September 1994 and the many publicationsidentified therein. Such materials are well known in the art and itwould not be difficult for a skilled artisan to formulate or use suchcomponents for purposes described herein. Some useful silver saltemulsions are described, for example in U.S. Pat. No. 7,351,523(Grzeskowiak), U.S. Pat. Nos. 5,589,318, and 5,512,415 (both to Dale etal.).

Useful silver halide emulsions containing silver halide grains that canbe reduced to silver metal particles can be prepared by any suitablemethod of grain growth, for example, by using a balanced double run ofsilver nitrate and salt solutions using a feedback system designed tomaintain the silver ion concentration in the growth reactor. Knowndopants can be introduced uniformly from start to finish ofprecipitation or can be structured into regions or bands within thesilver halide grains. Useful dopants include but are not limited to,osmium dopants, ruthenium dopants, iron dopants, rhodium dopants,iridium dopants, and cyanoruthenate dopants. A combination of osmium andiridium dopants such as a combination of osmium nitrosyl pentachlorideand iridium dopant is useful. Such complexes can be alternativelyutilized as grain surface modifiers in the manner described in U.S. Pat.No. 5,385,817 (Bell). Chemical sensitization can be carried out by anyof the known silver halide chemical sensitization methods, for exampleusing thiosulfate or another labile sulfur compound, alone or incombination with gold complexes.

Useful silver halide grains can be rounded cubic, octahedral, roundedoctahedral, polymorphic, tabular, or thin tabular emulsion grains. Suchsilver halide grains can be regular untwinned, regular twinned, orirregular twinned with cubic or octahedral faces. In one embodiment, thesilver halide grains can be rounded cubic having an ESD of less than 0.5μm and at least 0.05 μm.

Specific references relating to the preparation of emulsions ofdiffering halide ratios and morphologies include but are not limited toU.S. Pat. No. 3,622,318 (Evans); U.S. Pat. No. 4,269,927 (Atwell); U.S.Pat. No. 4,414,306 (Wey et al.); U.S. Pat. No. 4,400,463 (Maskasky);U.S. Pat. No. 4,713,323 (Maskasky); U.S. Pat. No. 4,804,621 (Tufano etal.); U.S. Pat. No. 4,783,398 (Takada et al.); U.S. Pat. No. 4,952,491(Nishikawa et al.); U.S. Pat. No. 4,983,508 (Ishiguro et al.); U.S. Pat.No. 4,820,624 (Hasebe et al.); U.S. Pat. No. 5,264,337 (Maskasky); U.S.Pat. No. 5,275,930 (Maskasky); U.S. Pat. No. 5,320,938 (House et al.);U.S. Pat. No. 5,550,013 (Chen et al.); U.S. Pat. No. 5,726,005 (Chen etal.); and U.S. Pat. No. 5,736,310 (Chen et al.).

Antifoggants and stabilizers can be added to give the silver halideemulsion the desired sensitivity, if appropriate. Useful antifoggantsinclude, for example, azaindenes such as tetraazaindenes, tetrazoles,benzotriazoles, imidazoles and benzimidazoles. Specific antifoggantsthat can be used include 6-methyl-1,3,3a,7-tetraazaindene,1-(3-acetamidophenyl)-5-mercaptotetrazole, 6-nitrobenzimidazole,2-methylbenzimidazole, and benzotriazole, individually or incombination.

The essential silver halide grains and hydrophilic binders or colloids,and optional addenda can be formulated and coated as a silver halideemulsion using suitable emulsion solvents including water andwater-miscible organic solvents. For example, useful solvents for makingthe silver halide emulsion or coating formulation can be water, analcohol such as methanol, a ketone such as acetone, an amide such asformamide, a sulfoxide such as dimethyl sulfoxide, an ester such asethyl acetate, liquid or low molecular weight poly(vinyl alcohol), or anether, or combinations of these solvents. The amount of one or moresolvents used to prepare the silver halide emulsions can be at least 30weight % and up to and including 50 weight % of the total formulationweight. Such coating formulations can be prepared using any of thephotographic emulsion making procedures that are known in the art.

Hydrophilic Overcoats

While the photosensitive silver halide emulsion layer, on either or bothsupporting sides of the transparent substrate, can be the outermostlayer in the precursor article, in many embodiments, there can be ahydrophilic overcoat disposed over each photosensitive silver halideemulsion layer. This hydrophilic overcoat can be the outermost layer inthe precursor (that is, there are no layers purposely placed over it oneither or both supporting sides of the transparent substrate). If bothsupporting sides of the transparent substrate comprise a photosensitivesilver halide layer, then a hydrophilic overcoat can be present on bothsupporting sides of the transparent substrate. Thus, a first hydrophilicovercoat is disposed over the first photosensitive silver halideemulsion layer, and a second hydrophilic overcoat is disposed over asecond photosensitive silver halide emulsion layer on the opposingsecond supporting side of the transparent substrate. In mostembodiments, each hydrophilic overcoat is directly disposed on eachphotosensitive silver halide emulsion layer, meaning that there are nointervening layers on the supporting sides of the transparent substrate.The chemical compositions and dry thickness of these hydrophilicovercoats can be the same or different, but in most embodiments theyhave essentially the same chemical composition and dry thickness on bothsupporting sides of the transparent substrate.

In some embodiments, each hydrophilic overcoat (first or second, orboth) comprises one or more silver halides in the same or differentamount so as to provide silver metal particles after exposure andprocessing, in an amount of at least 5 mg Ag/m² and up to and including150 mg Ag/m², or at least 5 mg Ag/m² and up to and including 75 mgAg/m². When present, the one or more silver halides in each hydrophilicovercoat can have a grain ESD of at least 100 nm and up to and including1000 nm, or at least 150 nm and up to and including 600 nm. In someembodiments, the one or more silver halides in each hydrophilic overcoathave a grain ESD that is larger than the grain ESD of the silver halidein the non-color hydrophilic photosensitive layer over which it isdisposed. In various embodiments, the silver halide(s) in eachhydrophilic overcoat comprises up to 100 mol % bromide or up to 100 mol% chloride, and up to and including 3 mol % iodide, all molar amountsbased on total silver content. In other embodiments, the silverhalide(s) in each hydrophilic overcoat comprises more chloride than thesilver halide in the non-color hydrophilic photosensitive layer overwhich it is disposed. This relationship can be the same or different onboth supporting sides of the transparent substrate in the “duplex”conductive film element precursors.

When present, the silver halide is dispersed (generally uniformly)within one or more hydrophilic binders or colloids in each hydrophilicovercoat, which hydrophilic binders or colloids include those describedabove for the non-color hydrophilic photosensitive layers. In manyembodiments, the same hydrophilic binders or colloids can be used in allof the layers of the precursor. However, different hydrophilic bindersor colloids can be used in the various layers, and on either or bothsupporting sides of the transparent substrate. The amount of one or morehydrophilic binders or colloids in each hydrophilic overcoat is the sameor different and generally at least 50 weight % and up to and including100 weight %, or typically at least 75 weight % and up to and including98 weight %, all based on total hydrophilic overcoat dry weight.

In some embodiments, the hydrophilic overcoat can further comprise oneor more radiation absorbers such as UV radiation absorbers in an amountof at least 5 mg/m² and up to and including 100 mg/m². Such UV radiationabsorbers can be “immobilized” meaning that they do not readily diffuseout of the hydrophilic overcoat.

The same hydrophilic binders or colloids are used if no silver halide ispresent, and in such embodiments, the hydrophilic binders or colloidscan comprise up to and including 100 weight % of the total hydrophilicovercoat dry weight.

Each hydrophilic overcoat can also comprise one or more hardeners for ahydrophilic binder or colloid (such as gelatin or a gelatin derivative).Useful hardeners are described above.

The dry thickness of the each hydrophilic overcoat can be at least 100nm and up to and including 800 nm or more particularly at least 300 nmand up to and including 500 nm. In embodiments containing silver halide,the grain ESD to dry thickness ratio in the hydrophilic overcoat can befrom 0.25:1 to and including 1.75:1 or more likely from 0.5:1 to andincluding 1.25:1.

Additional Layers:

In addition to the layers and components described above on one or bothsupporting sides of the transparent substrate, the precursors andelectrically-conductive articles can also include other layers that arenot essential but can provide additional properties or benefits,including but not limited to radiation absorbing filter layers, adhesionlayers, and other layers as are known in the black-and-whitephotographic art. The radiation absorbing filter layers can also beknown as “antihalation” layers that can be located between the essentiallayers and each supporting side of the transparent substrate. Forexample, each supporting side can have a radiation absorbing filterlayer disposed directly on it, and directly underneath thephotosensitive silver halide emulsion layer. Such radiation absorbingfilter layers can include one or more filter dyes that absorb in the UV,red, green, or blue regions of the electromagnetic spectrum, or anycombination thereof, and can be located between the transparentsubstrate and the photosensitive silver halide emulsion layer on each orboth supporting sides of the transparent substrate.

The duplex conductive film element precursors used in the presentinvention can comprise on the opposing second supporting side of thetransparent substrate, a second photosensitive silver halide emulsionlayer and optionally, a second hydrophilic overcoat disposed over thesecond photosensitive silver halide emulsion layer. A radiationabsorbing filter layer can be disposed between the opposing secondsupporting side of the transparent substrate and the secondphotosensitive silver halide emulsion layer, which radiation absorbingfilter layer can be the same as or different from the radiationabsorbing filter layer on the first supporting side of the transparentsubstrate. For example, such radiation absorbing filter layers caninclude one or more UV radiation absorbing compounds.

In many duplex conductive film element precursors, the secondphotosensitive silver halide emulsion layer and a second hydrophilicovercoat (if present) have the same composition as the firstphotosensitive silver halide emulsion layer and the first hydrophilicovercoat, respectively.

Preparing Conductive Film Element Precursors

The various layers are formulated using appropriate components andcoating solvents and are applied to one or both supporting sides of asuitable transparent substrate (as described above) using known coatingprocedures including those commonly used in the photographic industry(for example, bead coating, blade coating, curtain coating, spraycoating, and hopper coating). Each layer formulation can be applied toeach supporting side of the transparent substrate in single-passprocedures or in simultaneous multi-layer coating procedures. Knowndrying techniques can be used to dry each of the applied formulations.

Making Electrically-Conductive Articles

The resulting conductive film element precursors can be used immediatelyfor an intended purpose, or they can be stored in roll or sheet form forlater use. For example, the precursors can be rolled up duringmanufacture and stored for use in a roll-to-roll imaging and processingprocess, and subsequently cut into desired sizes and shapes.

To imagewise expose a precursor, a suitable mask element or group ofmask elements are designed with predetermined patterns for bothelectrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns that areeventually formed in the electrically-conductive articles. As notedabove, the photosensitive silver halide emulsion layers in theprecursors are generally designed to accommodate both touch regionshaving desired electrically-conductive silver metal electrode grids, andelectrode connector regions that contain desired electrically-conductivesilver connector wire patterns to provide designed circuitry. Both touchregions and electrode connector regions are formed in the samephotosensitive silver halide emulsion layer on one or both supportingsides of the transparent substrate. The transparent regions outside ofthe electrically-conductive silver metal electrode grids andelectrically-conductive silver connector wire patterns generally containno silver metal particles.

Thus, one or both sides of a precursor are designed to be exposed tosuitable radiation to provide, in each photosensitive silver halideemulsion layer: (a) a latent electrically-conductive silver metalelectrode grid, and (b) a latent electrically-conductive silverconnector wire pattern that is different from the latentelectrically-conductive silver metal electrode grid. Each side of theprecursor can be imagewise exposed at the same time or they can beimagewise exposed at different times using different mask elements sothe opposing latent images in all regions are different in design, size,surface area covered by silver metal particles, or sheet resistivity.Opposing photosensitive silver halide emulsion layers can also bedesigned to have different wavelength sensitivity so that differentimaging (exposing) radiation wavelengths can be used for exposure ofopposing supporting sides.

Thus, photosensitive silver halides in photosensitive silver halideemulsion layers can be imagewise exposed to appropriate actinicradiation (UV to visible radiation) from a suitable source that is wellknown in the art such as a xenon lamp, mercury lamp, or other source ofradiation of from 200 nm and up to and including 700 nm.

The exposed precursors can be processed using various aqueous-basedprocessing solutions including at least solution physical developmentand silver halide fixing, to provide in each exposed photosensitivesilver halide emulsion layer: (a) a electrically-conductive silver metalelectrode grid from the latent electrically-conductive silver metalelectrode grid, (b) an electrically-conductive silver connector wirepattern from the latent electrically conductive silver connector wirepattern, and (c) transparent regions outside of both theelectrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern.

The resulting electrically-conductive silver metal electrode grid isformed in the touch region and generally has an integrated transmittanceof at least 75% (for example, the electrically-conductive silver metalelectrode grid covers 25% or less of the total touch region surfacearea). Moreover, the resulting electrically-conductive silver connectorwire pattern is formed in the electrode connector region and generallyhas an integrated transmittance of 68% or less (or 50% or less). Thus,the electrically-conductive silver connector wire pattern generallycovers more than 42% of the total electrode connector region. Integratedtransmittance is determined as described above. These amounts can be thesame or different on opposing supporting sides of the transparentsubstrate.

Prebath solutions can also be used to treat the exposed silver saltsprior to development. Such solutions can include one or more developmentinhibitors as described above for the developing solutions, and in thesame or different amounts. Effective inhibitors include but are notlimited to, benzotriazoles, heterocyclic thiones, andmercaptotetrazoles. The prebath temperature can be in a range asdescribed for development. Prebath time depends upon the concentrationand particular inhibitor, but it can range from at least 10 seconds andup to and including 4 minutes.

Processing the exposed silver halide in the latent images is generallyaccomplished firstly with one or more development steps during whichsilver ions in the silver halide latent images are reduced to silvermetal (or silver particles). Such development steps are generallycarried out using known aqueous developing solutions that are commonlyused in silver metal image-forming black-and-white photography andtypically include at least one solution physical development solution.

Numerous silver metal image-forming black-and-white developing solutions(identified also as “developers”) are known that can develop the exposed(latent image containing) silver halides described above to form silvermetal particles. One commercial silver metal image-formingblack-and-white silver halide developer that is useful is Accumax®silver halide developer. Silver metal image-forming black-and-whitedeveloping solutions are generally aqueous solutions including one ormore silver halide developing agents, of the same or different type,including but not limited to those described in Research Disclosure Item17643 (December, 1978) Item 18716 (November, 1979), and Item 308119(December, 1989) such as polyhydroxybenzenes (such as dihydroxybenzene,or in its form as hydroquinone, cathecol, pyrogallol,methylhydroquinone, and chlorohydroquinone), aminophenols such asp-methylaminophenol, p-aminophenol, and p-hydroxyphenylglycine,p-phenylenediamines, ascorbic acid and its derivatives, reductones,erythrobic acid and its derivatives, 3-pyrazolidones such as1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-3-pyrazolidone, and1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, pyrazolone,pyrimidine, dithionite, and hydroxylamines. These developing agents canbe used individually or in combinations thereof. One or more developingagents can be present in suitable amounts for example of at least 0.01mol/l and up to and including 1 mol/l.

The black-and-white developing solutions can also include auxiliarysilver developing agents that exhibit super-additive properties with adeveloping agent. Such auxiliary developing agents can include but arenot limited to, p-aminophenols and substituted or unsubstitutedphenidones, in suitable amounts such as at least 0.001 mol/l and up toand including 0.1 mol/l.

The concentration of the one or more auxiliary silver developing agentscan be less than the concentration of the one or more developing agentsas described above.

Useful black-and-white developing solutions can also include one or moresilver complexing agents (or silver ligands) including but not limitedto, sulfite, thiocyanate, thiosulfate, thiourea, thiosemicarbazide,tertiary phosphines, thioethers, amines, thiols, aminocarboxylates,triazolium thiolates, pyridines (including bipyridine), imidazoles, andaminophosphonates, in suitable amounts. For example, one or more alkalimetal sulfites can be present in an amount of at least 0.1 mol/l and upto and including 1 mol/l

The black-and-white developing solutions can also comprise one or morealkyl- or aryl-substituted or unsubstituted mercaptotetrazoles insuitable amounts for various purposes such as at least 0.25 mmol/l andup to and including 2.5 mmol/l. Useful mercaptotetrazoles include butare not limited to, alkyl-, aryl-, and heterocyclyl-substitutedmercaptotetrazoles. Examples of such compounds include but are notlimited to, 1-phenyl-5-mercaptotetrazole (PMT),1-ethyl-5-mercaptotetrazole, 1-t-butyl-5-mercaptotetrazole, and1-pyridinyl-5-mercaptotetrazoles.

Moreover, the black-and-white developing solution can also include oneor more development inhibitors in suitable amounts. Useful developmentinhibitors include but are not limited to, substituted and unsubstitutedbenzotriazole compounds such as 5-methylbenzotriazole, imidazoles,benzimidazole thiones, benzothiazole thiones, benzoxazole thiones, andthiazoline thiones, all in the same or different amounts as describedabove for the mercaptotetrazoles.

Other addenda that can be present in the black-and-white developingsolutions in known amounts include but are not limited to, metalchelating agents, preservatives (such as sulfites), antioxidants, smallamounts of water-miscible organic solvents (such as benzyl alcohol anddiethylene glycol), nucleators, as well as acids, bases (such as alkalihydroxides), and buffers (such as carbonate, borax, phosphates, andother basic salts) to establish a pH of at least 8 and generally of a pHof at least 9.5, or at least 11 and up to and including 14.

The silver halide developing solution can be supplied at workingstrength or in concentrated form that is diluted prior to or during useup to 5 times with water.

Multiple development steps can be used if desired. For example, a firstdeveloping solution can provide initial development to form silver metalnuclei and then a second developing solution can be used to provide“solution physical development” that improves conductivity of theresulting silver metal images.

A solution physical development step can be carried out using a solutionhaving a pH of at least 8 and up to and including 13. This silver halidesolution physical developing solution can comprise one or more primarydeveloping agents chosen from one or more of hydroquinone or itsderivatives or one or more ascorbic acid or derivatives thereof. Theprimary developing agents in the silver halide solution physicaldeveloping solution can be the same or different as the primarydeveloping agents in the silver halide developing solution describedabove.

The one or more primary developing agents in the silver halide solutionphysical developing solution can be present in a total amount of atleast 0.01 mol/l and up to and including 1 mol/l.

In addition, the silver halide solution physical developing solutioncomprises one or more silver halide dissolution catalysts as essentialcomponents in an amount of at least 0.001 mol/l and up to and including0.1 mol/l, or typically of at least 0.005 mol/l and up to and including0.05 mol/l.

Useful silver halide dissolution catalysts include but are not limitedto, alkali metal thiocyanate salts such as sodium thiocyanate andpotassium thiocyanate, thioethers such as 3,6-dithia-1,8-octanediol, andheterocyclic thiones such astetrahydro-4,6-dimethyl-1,3,5-triazine-2(1H)-thione, andtetrahydro-3-hydroxyethyl-1,3,5-triazine-2(1H)-thione. These compoundscan readily complex with silver.

In some embodiments, the silver halide solution physical developingsolution contains substantially no catalytic developing agents such asthose compounds described above for the silver halide developingsolution. The term “substantially no” means that less than 0.001 mol/lor even less than 0.0001 mol/l of such compounds are purposelyincorporated into or created in the solution.

The silver halide solution physical developing solution can furthercomprise one or more alkali metal sulfites include sodium sulfite,potassium sulfite, and mixtures thereof. The alkali metal sulfites canbe present in the silver halide solution physical developing solution ina total amount of at least 0.2 mol/l and up to and including 3 mol/lwhen potassium sulfite or sodium sulfite is used or particularly whenonly potassium sulfite is used.

The silver halide solution physical developing solution can furtherinclude one or more polyaminopolycarboxylic acid salts that are capableof complexing with silver ion, including but not limited to,diethylenetriamine pentaacetic acid, pentasodium salt and other similarcompounds known in the art. Such compounds can be useful particularlywhen a sulfite is not present. Such compounds can be present in anamount of at least 0.001 mol/l and up to and including 0.03 mol/l.

The silver halide solution physical developing solution can also includeone or more metal ion complexing agents that can complex with silver,calcium, iron, magnesium, or other metal ions that can be present.Silver or calcium metal ion complexing agents can be particularly usefulin a total amount of at least 0.001 mol/l.

Particularly useful silver halide solution physical developing solutionsinclude but are not limited to, hydroquinone or a derivative thereof andsodium thiocyanate or potassium thiocyanate, and optionally a sulfiteand calcium or silver metal ion complexing agent.

The silver halide physical solution developing solution can be providedat working strength or in a concentrated form that is suitably dilutedprior to or during processing using known processing equipment andprocedures. For example, the silver halide physical developing solutioncan be concentrated at least 4 times compared to a desired workingstrength concentration.

Useful development temperatures can range from at least 15° C. and up toand including 60° C. Useful development times can range from at least 10seconds and up to and including 10 minutes but more likely up to andincluding 1 minute. The same time or temperature can be used forindividual development steps and can be adapted to develop at least 90mol % of the exposed silver halide in all latent silver halide images.If a prebath solution is not used, the development time can be extendedappropriately. Any exposed silver halide(s) in a hydrophilic overcoat isalso developed during the development step(s). Washing or rinsing can becarried out with water after or between any development steps.

After development of the exposed silver halide to silver metal, theundeveloped silver halide in all photosensitive silver halide emulsionlayers is generally removed by treating the developed silver-containingarticle with a silver halide fixing solution. Silver halide fixingsolutions are well known in the black-and-white photographic art andcontain one or more compounds that complex the silver ion for removalfrom the layers. Thiosulfate salts are commonly used in silver halidefixing solutions. The silver halide fixing solution can optionallycontain a hardening agent such as alum or chrome-alum. The developedfilm can be processed in a silver halide fixing solution immediatelyafter development, or there can be an intervening stop bath or waterwash or rinse, or both stop bath and water rinse. Fixing can be carriedout at any suitable temperature and time such as at least 20° C. for atleast 30 seconds.

Fixing then leaves the silver metal particles in theelectrically-conductive silver metal electrode grid andelectrically-conductive silver connector wire pattern in each formerlyphotosensitive silver halide emulsion layer. Fixing also removes anynon-developed silver halide in any hydrophilic overcoat.

After fixing, the resulting intermediate article can be washed or rinsedin water that can optionally include surfactants or other materials toreduce water spot formation upon drying.

In addition, after fixing and washing, the intermediate article can befurther treated to further enhance the conductivity of the silver metalon each supporting side of the transparent substrate. A variety of wayshave been proposed to carry out this “conductivity enhancement” process.For example, U.S. Pat. No. 7,985,527 (Tokunaga) and U.S. Pat. No.8,012,676 (Yoshiki et al.) describe conductivity enhancement treatmentsusing hot water baths, water vapor, reducing agents, or halides.

It is also possible to enhance conductivity of the silver metalparticles by repeated contact with a conductivity enhancing agent,washing, drying, and repeating this cycle of treating, washing, anddrying one or more times. Useful conductivity enhancing agents includebut are not limited to, sulfites, borane compounds, hydroquinones,p-phenylenediamines, and phosphites. The treatment can be carried out ata temperature of at least 30° C. and up to and including 90° C. for atleast 0.25 minute and up to and including 30 minutes.

It can be useful in some embodiments to treat theelectrically-conductive article with a hardening bath after fixing andbefore drying to improve the physical durability of the resultingelectrically-conductive article. Such hardening baths can include one ormore known hardening agents in appropriate amounts that would be readilyapparent to one skilled in the art. It can be desired to control theswelling of the conductive film element precursor at one or more stagesof processing, so that swelling is limited to a desired amount of theoriginal precursor dry thickness.

Additional treatments such as a stabilizing treatment can also becarried out before a final drying if desired, at any suitable time andtemperature.

Drying at any stage can be accomplished in ambient conditions or byheating, for example, in a convection oven at a temperature above 50° C.but below the glass transition temperature of the transparent substrate.

While imagewise exposing and processing of each side of the precursorcan be carried out at different times or sequences, in many embodiments,imagewise exposing and processing of the photosensitive silver halideemulsion layer on the opposing second supporting side is carried outsimultaneously with imagewise exposing and processing of thephotosensitive silver halide emulsion layer on the first supportingside.

The result of the processing steps is an electrically-conductive articleof the present invention of any of the embodiments described above.

Electrically-conductive Silver Metal Electrode Grids:

The electrically-conductive silver metal electrode grid on the firstsupporting side and the optional electrically-conductive silver metalgrid on the opposing second supporting side can be the same or differentin composition, pattern arrangement, conductive line thickness, or shapeof the grid lines (for example, a pattern of polygons including but notlimited to, a pattern of rectangles, triangles, hexagons, rhombohedrals,octagons, or squares), circles or other curved lines, or randomstructures, all corresponding to the predetermined pattern in the maskelement used during imagewise exposure. For example, in one embodiment,the electrically-conductive silver metal electrode grid on the firstsupporting side can be arranged in a square pattern, and theelectrically-conductive silver metal electrode grid on the opposingsupporting second side can be arranged in a diamond pattern. In eachinstance, the silver grid lines in the electrically-conductive silvermetal grids form a net-like structure. In other embodiments, the variouspatterns on opposing supporting sides can be arranged in an alternativearrangement so that the electrically-conductive silver metal electrodegrid on one supporting only partially covers the electrically-conductivesilver metal electrode grid on the opposing supporting side, somewhat asis shown in FIG. 14 of U.S. Patent Application Publication 2011/0289771(noted above).

The electrically-conductive silver wires in the electrically-conductivesilver metal electrode grid can have any desired length that is usuallyat least 1 cm and up to and including 10 meters, and they can have anaverage dry thickness (line width, one outer edge to the other outeredge) and dry height that are the same or different, and are generallyless than 50 μm, but more likely at least 1 μm and up to and including20 μm, or particularly at least 5 μm and less than 15 μm or even 10 μmor less.

Electrically-Conductive Silver Connector Wire Patterns:

Each electrically-conductive silver connector wire pattern comprises atleast one and more likely at least two adjacent (for example, at leastfirst and second) silver main wires, and there can be up to 1000 or evenmore of these silver main wires in each electrically-conductive silverconnector wire pattern. The number of silver main wires can be differenton opposing supporting sides of the transparent substrate. Each silvermain wire comprises two or more (and up to 10 or even more) silvermicro-wires that are electrically connected to a silver end wire at anend of the at least one (or generally two adjacent) silver main wires.Thus, the two or more silver micro-wires and the silver end wire in eachsilver main wire form a bundled pattern. Many bundled patterns comprisea plurality of silver main wires, each of which comprises a plurality ofsilver micro-wires and all of the silver micro-wires are electricallyconnected at both ends to suitable silver end wires. As described below,such bundled patterns can also include one or more silver cross-wires.

In some embodiments, each silver main wire can comprise from two toeight silver micro-wires that, with the suitable silver end wires, forma bundled pattern. Thus, each bundled pattern in such embodimentscomprises an electrically-conductive silver end wire at each end of theat least two adjacent silver main wires (and thus at the end of eachpair of adjacent silver main wires in the bundled pattern) thatelectrically connects with the two to eight silver micro-wires in eachbundled pattern.

The average distance between any two adjacent silver main wires isgreater than the average distance between any two adjacent silvermicro-wires in each bundled pattern. For example, the average distancebetween any two adjacent silver main wires can be greater than theaverage distance between any two adjacent silver micro-wires in eachbundled pattern by at least 30%, or more typically at least 100%. Forexample, the average distance between two adjacent silver main wires canbe at least 5 μm, or at least 10 μm, or even at least 20 μm. Such“average distances” are measured from the outer edge of a given silvermicro-wire to the nearest outer edge of an adjacent silver micro-wire,of from the outer edge of the outermost silver micro-wire in a givensilver main wire to the outer edge of the closest outermost silvermicro-wire in an adjacent silver main wire.

Within each silver main wire, the average total length of each silvermicro-wire can be at least 1 mm or typically at least 5 mm and up to andincluding 1000 mm.

The average distance between any two adjacent silver micro-wires in eachbundled pattern (of each and any silver main wire) can be at least 2 μmand up to and including 10 μm (wherein “average distance” is definedabove). In particular, the average distance between any two adjacentsilver micro-wires in each bundled pattern (or each and any silver mainwire) can be at least 5 μm and up to and including 8 μm.

The ratio of the average width (outer edge to opposing outer edge) ofeach silver micro-wire to the average distance between two adjacentsilver micro-wires in each bundled pattern (or each and any silver mainwire) can be at least 0.5:1 but less than 2:1, or typically at least 1:1and up to and including 2:1.

It is also desirable that for each silver micro-wire, the ratio ofmaximum height to minimum height can be at least 1.05:1, or typically atleast 1.1:1. In some embodiments of at least one of the silvermicro-wires (and in most embodiments, each silver micro-wire), themaximum height of the silver micro-wire can be equivalent (varying byless than 10%) to the center height of the silver micro-wire wherein the“center” is determined to be essentially equidistant between the twoouter edges of the silver micro-wire. “Essentially equidistant” meansthat the distances between the two outer edges vary by no more than 10%.

In other embodiments of at least one of the silver micro-wires (and inmost embodiments, each silver micro-wire), the maximum height can becloser to a micro-wire outer edge than to micro-wire center height (atleast 51% closer to the outer edge than to the center). For example, themaximum height can actually be located at one or both outer edges ofsome silver micro-wires.

It is also possible that for each silver micro-wire, the ratio ofmaximum height to average height can be at least 1.01:1, or moretypically at least 1.01:1 to and including 1.05:1.

The average width of each silver micro-wire (from one outer edge to theother outer edge) in each bundled pattern can be at least 2 μm and up toand including 20 μm, or typically up to and including 15 μm or typicallyfrom 2 μm and up to and including 12 μm.

Moreover, each bundled pattern can comprise at least one silvercross-wire between adjacent silver micro-wires that is not at the end ofthe adjacent silver micro-wires. Typically, adjacent silver micro-wirescomprise multiple silver cross-wires that are not at the end of theadjacent silver micro-wires. A skilled worker can design each bundledpattern to have as many silver cross-wires as can be desired for a givenelectrically-conductive silver connector wire pattern.

The silver cross-wires can be arranged in any suitable frequency ordirectional arrangement and such arrangement can be the same ordifferent for each set of adjacent silver micro-wires.

For example, each bundled pattern can comprise multiple (two or more)silver cross-wires between adjacent silver micro-wires, wherein themultiple silver cross-wires are arranged at a distance from each otherof at least 100 μm.

Moreover, each bundled pattern can comprise multiple (two or more)silver cross-wires in a set of adjacent silver micro-wires that areoffset from multiple silver cross-wires in an another set of adjacentsilver micro-wires (for example alternating along the adjacent sets ofadjacent silver micro-wires). All of the silver cross-wires cantherefore be arranged in the same or different manner among all of theadjacent sets of adjacent silver micro-wires.

In some embodiments, each of the multiple silver cross-wires issubstantially perpendicular (intersection at an angle of substantially90°) to the adjacent silver micro-wires. In other embodiments, each ofthe multiple silver cross-wires intersects the adjacent silvermicro-wires at an angle that is greater than or less than 90°. The twoor more silver micro-wires can be substantially parallel (for example,the adjacent silver micro-wires are substantially parallel).

The present invention can also be exemplified in reference to FIGS. 1-11that are now explained.

In FIG. 1, electrically-conductive article 5 has transparent substrate40 on which electrically-conductive silver connector wire pattern 8 isdisposed, which electrically-conductive silver connector wire pattern 8comprises multiple silver main wires 10. Each silver main wire 10comprises multiple adjacent silver micro-wires 20 (four shown in FIG. 1for each silver main wire 10). Silver end wire 22 is shown at the end ofeach silver main wire 10. Outside of electrically-conductive silverconnector wire pattern 8 is transparent region 50 (referenced in somebut not all places). Transparent regions (not shown with additionalreference numbers) are also present between (or outside) adjacent silvermain wires 10 and between (or outside) adjacent silver micro-wires 20 ineach silver main wire 10. All transparent regions contain no significantsilver halide or silver metal. In electrically-conductive article 5,adjacent silver main wires (at least one identified as 10) are separatedby distance S1 and the distance between adjacent silver micro-wires (oneidentified as 20) is shown by S2. As described above, the average S1 isgreater than the average S2 in each bundled pattern (silver main wire10). Representative average silver micro-wire 20 width is shown as W andaverage silver micro-wire length is shown as L. Each silver micro-wire20 can have essentially the same or different L and W dimensions. Inmost embodiments, such dimensions are the same for each silvermicro-wire in a given silver main wire.

FIG. 2 shows a schematic cross-section of electrically-conductivearticle 5 comprising transparent substrate 40 having first supportingside 42 and opposing second supporting side 44. A representative silvermicro-wire 20 is shown on both first supporting side 42 and opposingsecond supporting side 44.

In the cross-section view shown in FIG. 3A, a portion of photosensitivesilver halide emulsion layer 15 is disposed on a supporting side (eitherfirst supporting side or opposing second supporting side) of transparentsubstrate 40 having first supporting side 42 and opposing secondsupporting side 44. This portion of photosensitive silver halideemulsion layer 15 contains multiple non-exposed and non-developed silverhalide grains 60 surrounded by hydrophilic binder 64.

FIG. 3B shows a similar view as FIG. 3A but silver micro-wire 20 isdisposed on transparent substrate 40 having first supporting side 42 andopposing second supporting side 44, which silver micro-wire 20 containsmultiple silver metal particles 62 that can be derived from exposure andsilver halide development of the multiple silver halide grains 60surrounded by hydrophilic binder 64, shown in the portion ofphotosensitive silver halide emulsion layer 15 illustrated in FIG. 3A.

FIG. 4 is similar to FIG. 1 and shows electrically-conductive article 5comprising transparent substrate 40 on which electrically-conductivesilver connector wire pattern 8 is disposed. Electrically-conductivesilver connector wire pattern 8 comprises multiple silver main wires 10.Only three silver main wires 10 are shown but electrically-conductivesilver connector wire pattern 8 can have as few as two silver mainwires. Moreover, while only four silver micro-wires 20 are shown foreach silver main wire 10, the number of silver micro-wires in each mainwire can be as few as two and up to and including ten. Silver end wires22 are shown at the end of each set of adjacent silver micro-wires 20and various silver cross-wires 24 (only some are referenced) are shownat the same interval along silver micro-wires 20. Outside ofelectrically-conductive silver connector wire pattern 8 is transparentregion 50 (referenced in only some places), but transparent regions (notreferenced) also exist between adjacent silver micro-wires and betweenadjacent silver main wires.

FIG. 5 is similar to FIG. 4 but silver cross-wires 24 are arranged atdifferent intervals along silver micro-wires 20 and are offset betweenpairs of adjacent silver micro-wires 20. Thus, each bundled pattern orsilver main wire 10 comprises multiple silver cross-wires 24 in a set ofadjacent silver micro-wires 20, which are offset from multiple silvercross-wires 24 in an adjacent set of adjacent silver micro-wires 20.

FIG. 6 shows representative portions of some embodiments of the methodused to make the electrically-conductive articles in which a conductivefilm element precursor (“precursor”) is provided in feature 100,imagewise exposed to suitable radiation in feature 105, and theresulting latent silver is processed [including development usingsuitable silver metal image-forming black-and-white developingsolution(s)] in the precursor in feature 110.

FIG. 7 shows representative portions of other embodiments in which aprovided duplex conductive film element precursor (“precursor”) isimagewise exposed in feature 105 in two individual features of imagewiseexposure of a first side of the duplex conductive film element precursorin feature 107 and sequential imagewise exposure of the second (oropposing) side of the duplex conductive film element precursor infeature 109, followed by processing (including development) of theresulting latent silver in both imagewise exposed sides of the precursorin feature 110.

FIG. 8 shows representative portions of yet another variation in whichimagewise exposure feature 105 is carried out simultaneously for bothfirst and second sides of a duplex conductive film element precursor(“precursor”) as shown in features 107 and 109, and then followed byprocessing (including development) of latent silver on both sides of theimagewise exposed precursor in feature 110.

Still other representative portions of the method of this invention areshown in FIG. 9 in which imagewise exposure of a first side of a duplexconductive film element precursor (“precursor”) is provided in 107,which imagewise exposed first side is then processed (for example,development) to provide silver metal particles from latent silver infeature 112. The second (or opposing) side of the duplex conductive filmelement precursor is then imagewise exposed in 109 following byappropriate processing (including development) of latent silver tosilver metal particles in the precursor in feature 114.

FIG. 10 is a schematic cross-sectional view of a typical silvermicro-wire 20 that has a rounded upper and outer surface, and isdisposed on transparent substrate 40 having first supporting side 42 andopposing second supporting side 44. Silver micro-wire 20 is thereforecomposed of multiple silver metal particles 62 surrounded by hydrophilicbinder 64, which have been derived for example from appropriate silverhalide grains using the chemical compositions, appropriate exposure, andprocessing chemistry described above. As shown in FIG. 10, silvermicro-wire 20 has average width W, silver micro-wire maximum height D1,and silver micro-wire minimum height D2, wherein silver micro-wiremaximum height D1 is greater than silver micro-wire minimum height D2for example by a ratio of at least 1.05:1. While FIG. 10 illustrates asilver micro-wire that has uniform dimensions and contours, it would beunderstood by a skilled artisan that the drawn illustration isrepresentative only and that actual silver micro-wires produced in thepractice of this invention can have more irregular outer surfaces andshapes.

FIG. 11 is another schematic cross-sectional view showing a differentshape for silver micro-wire 20 containing multiple silver metalparticles 62 surrounded in hydrophilic binder 64, which silvermicro-wire 20 is disposed on transparent substrate 40 having firstsupporting side 42 and opposing second supporting side 44. Silvermicro-wire minimum height D2 is at or near the center of silvermicro-wire 20, and silver micro-wire minimum height D2 is less thansilver micro-wire maximum height D1 that is near or at either or bothouter edges of silver micro-wire 20. As one skilled in the art wouldunderstand, such illustration of silver micro-wire 20 is representativeonly and actual silver micro-wires produced in the practice of thisinvention can exhibit maximum and minimum heights that vary considerablyfrom that shown and can thus have more irregular outer surfaces.

The present invention provides at least the following embodiments andcombinations thereof, but other combinations of features are consideredto be within the present invention as a skilled artisan would appreciatefrom the teaching of this disclosure:

1. An electrically-conductive article comprising a transparent substratehaving a first supporting side and an opposing second supporting side,

the first supporting side comprising: (a) an electrically-conductivesilver metal electrode grid, (b) an electrically-conductive silverconnector wire pattern, and optionally, (c) transparent regions outsideof both the electrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern,

wherein:

(i) the electrically-conductive silver connector wire pattern comprisesat least one silver main wire that comprises two or more silvermicro-wires that are electrically connected to a silver end wire at anend of the at least one silver main wire, the silver micro-wires and thesilver end wire in the at least one silver main wire forming a bundledpattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between any two adjacent silver micro-wires in eachbundled pattern is at least 0.5:1 but less than 2:1; and

(iv) the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 68%.

2. The electrically-conductive article of embodiment 1, wherein theelectrically-conductive silver connector wire pattern comprises at leasttwo adjacent silver main wires, and the average distance between the atleast two adjacent silver main wires is greater than the averagedistance between any two adjacent silver micro-wires in each bundledpattern.

3. The electrically-conductive article of embodiment 2, wherein theaverage distance between any two adjacent silver micro-wires in eachbundled pattern is at least 2 μm and up to and including 10 μm.

4. The electrically-conductive article of any of embodiments 1 to 3,further comprising on the opposing second supporting side of thetransparent substrate: (a) an opposing electrically-conductive silvermetal electrode grid, (b) an opposing electrically-conductive silverconnector wire pattern, and optionally, (c) transparent regions outsideof both the opposing electrically-conductive silver metal electrode gridand the opposing electrically-conductive silver connector wire pattern,

wherein, on the opposing second supporting side of the transparentsubstrate:

(i) the opposing electrically-conductive silver connector wire patterncomprises at least one silver main wire that comprises two or moresilver micro-wires that are electrically connected to a silver end wireat an end of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern;

(ii) the average length of each silver micro-wire is at least 1 mm;

(iii) the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 0.5:1 but less than 2:1; and

(iv) the opposing electrically-conductive silver connector wire patternhas an integrated transmittance of less than 68%.

5. The electrically-conductive article of embodiment 4, wherein theopposing electrically-conductive silver connector wire pattern comprisesat least two adjacent silver main wires, and the average distancebetween these at least two adjacent silver main wires is greater thanthe average distance between any two adjacent silver micro-wires in eachbundled pattern.

6. The electrically-conductive article of embodiment 5, wherein theaverage distance between any two adjacent silver micro-wires in eachbundled pattern on the opposing second supporting side of thetransparent substrate is at least 2 μm and up to and including 10 μm.

7. The electrically-conductive article of any of embodiments 1 to 6,wherein for each silver micro-wire, the ratio of maximum height tominimum height is at least 1.1:1.

8. The electrically-conductive article of any of embodiments 1 to 7,wherein the at least one silver micro-wire has a maximum height that isits center height.

9. The electrically-conductive article of any of embodiments 1 to 7,wherein the at least one silver micro-wire has a maximum height that iscloser to its outer edge than to its center.

10. The electrically-conductive article of any of embodiments 1 to 9,wherein the average width of each silver micro-wire is at least 0.5 μmand up to and including 10 μm.

11. The electrically-conductive article of any of embodiments 1 to 10,wherein each bundled pattern comprises at least one silver cross-wirebetween adjacent silver micro-wires that is not at the end of theadjacent silver micro-wires.

12. The electrically-conductive article of any of embodiments 1 to 11,wherein each bundled pattern comprises multiple silver cross-wiresbetween adjacent silver micro-wires, wherein the multiple silvercross-wires are arranged at a distance from each other of at least 100μm.

13. The electrically-conductive article of any of embodiments 1 to 12,wherein each bundled pattern comprises multiple silver cross-wires in aset of adjacent silver micro-wires that are offset from multiple silvercross-wires in another set of adjacent silver micro-wires.

14. The electrically-conductive article of claim 12 or 13, wherein eachof the multiple silver cross-wires is substantially perpendicular to theadjacent silver micro-wires.

15. The electrically-conductive article of any of embodiments 1 to 14,wherein the at least one silver main wire comprises from two to tensilver micro-wires in a bundled pattern.

16. The electrically-conductive article of any of embodiments 1 to 15,wherein the average distance between any at least two adjacent silvermain wires is greater than the average distance between any two adjacentsilver micro-wires in each bundled pattern by at least 30%.

17. The electrically-conductive article of any of embodiments 1 to 16,wherein the ratio of the average width of each silver micro-wire to theaverage distance between two adjacent silver micro-wires in each bundledpattern is at least 1:1 and up to and including 2:1.

18. The electrically-conductive article of any of embodiments 1 to 17,wherein the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 50% and theelectrically-conductive silver metal electrode grid has an integratedtransmittance of at least 90%.

19. An electrically-conductive article comprising a transparentsubstrate having a first supporting side and an opposing secondsupporting side,

the first supporting side comprising: (a) an electrically-conductivesilver metal electrode grid, (b) an electrically-conductive silverconnector micro-wire pattern comprising at least one silver micro-wire,and optionally, (c) transparent regions outside of both theelectrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern,

wherein the ratio of maximum height to minimum height of the at leastone silver micro-wire is at least 1.05:1.

20. The electrically-conductive article of embodiment 19, wherein the atleast one silver micro-wire has an average width of at least 5 μm and upto and including 20 μm.

21. The electrically-conductive article of embodiment 19 or 20, whereinthe electrically-conductive silver connector wire pattern comprises atleast two adjacent silver main wires, and the average distance betweenthe at least two adjacent silver main wires is greater than the averagedistance between any two adjacent silver micro-wires in each bundledpattern.

22. The electrically-conductive article of embodiment 21, wherein theaverage distance between any two adjacent silver micro-wires in eachbundled pattern is at least 2 μm and up to and including 10 μm.

23. The electrically-conductive article of any of embodiments 19 to 22,further comprising on the opposing second supporting side of thetransparent substrate: (a) an opposing electrically-conductive silvermetal electrode grid, (b) an opposing electrically-conductive silverconnector wire pattern, and optionally, (c) transparent regions outsideof both the opposing electrically-conductive silver metal electrode gridand the opposing electrically-conductive silver connector wire pattern,

wherein the ratio of maximum height to minimum height of the at leastone silver micro-wire on the opposing second supporting side of thetransparent substrate is at least 1.05:1.

24. The electrically-conductive article of embodiment 23, wherein theopposing electrically-conductive silver connector wire pattern comprisesat least two adjacent silver main wires, and the average distancebetween these at least two adjacent silver main wires is greater thanthe average distance between any two adjacent silver micro-wires in eachbundled pattern.

25. The electrically-conductive article of embodiment 24, wherein theaverage distance between any two adjacent silver micro-wires in eachbundled pattern on the opposing second supporting side of thetransparent substrate is at least 2 μm and up to and including 10 μm.

26. The electrically-conductive article of any of embodiments 19 to 25,wherein for each silver micro-wire, the ratio of maximum height tominimum height is at least 1.1:1.

27. The electrically-conductive article of any of embodiments 19 to 26,wherein the at least one silver micro-wire has a maximum height that isits center height.

28. The electrically-conductive article of any of embodiments 19 to 27,wherein the at least one silver micro-wire has a maximum height that iscloser to its outer edge than to its center height.

29. The electrically-conductive article of any of embodiments 19 to 28,wherein the at least one silver micro-wire has an average width of atleast 5 μm and up to and including 10 μm.

30. The electrically-conductive article of any of embodiments 19 to 29,wherein each bundled pattern comprises at least one silver cross-wirebetween adjacent silver micro-wires that is not at the end of theadjacent silver micro-wires.

31. The electrically-conductive article of any of embodiments 19 to 30,wherein each bundled pattern comprises multiple silver cross-wiresbetween adjacent silver micro-wires, wherein the multiple silvercross-wires are arranged at a distance from each other of at least 100μm.

32. The electrically-conductive article of any of embodiments 19 to 31,wherein each bundled pattern comprises multiple silver cross-wires in aset of adjacent silver micro-wires that are offset from multiple silvercross-wires in another set of adjacent silver micro-wires.

33. The electrically-conductive article of embodiment 32, wherein eachof the multiple silver cross-wires is substantially perpendicular to theadjacent silver micro-wires.

34. The electrically-conductive article of any of embodiments 19 to 33,wherein the at least one silver main wire comprises from two to tensilver micro-wires in a bundled pattern.

35. The electrically-conductive article of any of embodiments 19 to 34,wherein the average distance between any at least two adjacent silvermain wires is greater than the average distance between any two adjacentsilver micro-wires in each bundled pattern by at least 30%.

36. The electrically-conductive article of any of embodiments 19 to 35,wherein the ratio of the average width of the at least one silvermicro-wire to the average distance between two adjacent silvermicro-wires in each bundled pattern is at least 1:1 and up to andincluding 2:1.

37. The electrically-conductive article of any of embodiments 19 to 36,wherein the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 68% and the conductive silvermetal electrode grid has an integrated transmittance of at least 90%.

38. A touch screen device comprising the electrically-conductive articleof any of embodiments 1 to 37.

39. A method for providing an electrically-conductive article of any ofembodiments 1 to 38, the method comprising:

imagewise exposing a conductive film element precursor that comprises atransparent substrate comprising a first supporting side and an opposingsecond supporting side and a photosensitive silver halide emulsion layeron at least the first supporting side, to radiation to provide, in thephotosensitive silver halide emulsion layer on at least the firstsupporting side: (a) a latent electrically-conductive silver metalelectrode grid, (b) an latent electrically-conductive silver connectorwire pattern different from the latent electrically-conductive silvermetal electrode grid, and optionally, (c) transparent regions outside ofboth the latent electrically-conductive silver metal electrode grid andthe latent electrically-conductive silver connector wire pattern; and

processing the latent electrically-conductive silver metal electrodegrid and the latent electrically-conductive silver connector wirepattern using at least solution physical development and silver halidefixing, to provide: (a) an electrically-conductive silver metalelectrode grid from the latent electrically-conductive silver metalelectrode grid, (b) an electrically-conductive silver connector wirepattern from the latent electrically-conductive silver connector wirepattern, and optionally, (c) transparent regions outside of both theelectrically-conductive silver metal electrode grid and theelectrically-conductive silver connector wire pattern according to anyof embodiments 1 to 38.

The present invention can be carried out using a photosensitive silverhalide emulsion layer (from the silver halide emulsion described below)that can be disposed on one or both supporting sides of a transparentpoly(ethylene terephthalate) film substrate in any suitable coatingmanner to form a conductive film element precursor used in the presentinvention.

The conductive film element precursors can also be prepared using a 100μm poly(ethylene terephthalate) substrate on which any suitablenon-color photosensitive silver halide emulsion can be hardened usingBVSM [1,1′-(methylene(sulfonyl))bis-ethane] and disposed at 0.5 weight %of total gelatin. However, underneath the silver halide emulsion layer,a filter layer can be directly disposed on the transparent substrate forUV absorption, containing 1500 mg/m² of gelatin and 300 mg/m² ofTINUVIN® 328 UV absorbing dye (for example, from BASF).

The non-color photosensitive silver halide emulsion layer can beprovided with a silver (Ag) to gelatin weight ratio of 2.33:1 (or at avolume ratio of about 0.233:1). If desired, an outermost hydrophilicovercoat layer can be provided over the non-color photosensitive silverhalide emulsion layer, containing 488 mg/m² of gelatin, 6 mg/m² of 0.6μm insoluble polymeric matte particles, and conventional coatingsurfactants.

This conductive film element precursor can be imagewise exposed on oneor both sides using a suitable exposing device through the same ordifferent mask elements that have predetermined reverse images for theeventual desired electrically-conductive silver wire electrode grid andan electrically-conductive silver connector wire pattern on one or bothsupporting sides of the precursor. Upon exposure of one or bothphotosensitive silver halide emulsion layers, (a) a latentelectrically-conductive silver wire electrode grid, (b) a latentelectrically-conductive silver connector wire pattern different from thelatent electrically-conductive silver wire electrode grid, andoptionally, (c) transparent regions outside of both the latentelectrically-conductive silver halide electrode grid and the latentelectrically-conductive silver connector wire pattern can be formed.

Following imagewise exposure, each latent electrically-conductive silvermetal electrode grid and latent electrically-conductive silver connectorwire pattern can be processed using at least solution physicaldevelopment and silver halide fixing, to provide: (a) anelectrically-conductive silver metal electrode grid from the latentelectrically-conductive silver metal electrode grid, (b) anelectrically-conductive silver connector wire pattern from the latentelectrically-conductive silver connector wire pattern, and (c)transparent regions outside of both the electrically-conductive silvermetal electrode grid and the electrically-conductive silver connectorwire pattern, in a resulting electrically-conductive article.

Such processing can be carried out using the processing solutionsdescribed below, so that the resulting electrically-conductive articlewould have one or more of the properties (i) through (v) describedabove.

TABLE I Processing Sequence Processing Processing Time, ProcessingStep/Solution Temperature (° C.) (minutes) Developing/developer 1 40 0.5Washing/rinsing with water 40 1.0 Developing/developer 2 40 3.0Fixing/fixing solution 40 1.77 Washing/rinsing with water 40 1.0Conductivity 60 2.0 Enhancement/Conductivity Enhancement SolutionWashing rinsing with water 40 1.0 Drying 60 15.0 Conductivity 60 2.0Enhancement/Conductivity Enhancement Solution Washing/rinsing with water40 1.0 Drying 60 15.0 Conductivity 60 2.0 Enhancement/ConductivityEnhancement Solution Washing/rinsing with water 40 1.0 Drying 60 15.0Stabilizing/Stabilizer Solution 40 1.0 Washing/rinsing with water 40 1.0

The aqueous processing solutions that can be used in the notedprocessing steps are described below in TABLES II through VI, all ofwhich can be prepared in de-mineralized water. Drying can be carried outusing a convection oven.

TABLE II Developer 1 Component Amount (g/liter) Potassium Hydroxide(45.5 wt. %) 10.83 Sodium Bromide 5.00 4,4-Dimethyl-1-phenyl-3- 0.33pyrazolidinone 1-Phenyl-5-mercaptotetrazole 0.13 5-methylbenzotriazole*0.17 Sodium hydroxide (50 wt. %) 1.82 Phosphonic acid, 0.29[nitrilotris(methylene)]tris-, pentasodium saltN,N′-1,2-ethanediylbis(N- 1.77 (carboxymethyl)glycine, Sodium carbonatemonohydrate 8.33 Potassium Sulfite (45 wt. %) 83.33 Hydroquinone 12.505,5′-[Dithiobis(4,1- 0.12 phenyleneimino)]bis(5-oxo- pentanoic acid

TABLE III Developer 2 Component Amount (g/liter) Sodium Sulfite 92.54Hydroquinone 4.63 N,N-bis(2-(bis(carboxymethyl)- 0.950amino)ethyl)-glycine, pentasodium salt Sodium tetraborate pentahydrate2.830 Sodium thiocyanate 0.42

TABLE IV Fixing Solution Component Amount (g/liter) Acetic Acid 24.43Sodium hydroxide (50 wt. %) 10.25 Ammonium thiosulfite 246.50 Sodiummetabisulfite 15.88 Sodium tetraborate pentahydrate 11.18 Aluminumsulfate (18.5 wt. %) 36.26

TABLE V Conductivity Enhancement Solution Component Amount (g/liter)[1,2-Bis(3-aminopropylamino)- 11.15 ethane] Triethanolamine (99 wt. %)38.6 Triethanolamine hydrochloride 14.0 Dimethylaminoborane 12.0 Sodiumlauryl sulfate 0.030 2,2-Bipyridine 1.00

TABLE VI Stabilizer Solution Component Amount (g/liter) Sodium hydroxide(50 wt. %) 0.29 N-[3-(2,5-dihydro-5-thioxo-1H- 0.82tetrazol-1-yl)phenyl]acetamide

Other electrically-conductive articles can be similarly prepared from aconductive film element precursor that differs from those describedabove only in the composition of the hydrophilic overcoat layer that canbe as follows:

488 mg/m² of gelatin, 6 mg/m² of 0.6 μm insoluble polymeric matteparticles, 20 mg/m² of a silver halide emulsion having a composition of98 mol % silver chloride and 2 mol % silver iodide (emulsion grainshaving rounded cubic morphology and an edge length 0.36 μm), 25 mg/m² ofTINUVIN® 328 UV radiation absorber, and conventional surfactants.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

PARTS LIST

-   5 Electrically-conductive article-   8 Electrically-conductive silver connector wire pattern-   10 Silver main wire-   15 Portion of photosensitive silver halide emulsion layer-   20 Silver micro-wire-   22 Silver end wire-   24 Silver cross-wire-   40 Transparent substrate-   42 First supporting side (of transparent substrate)-   44 Opposing second supporting side (or transparent substrate)-   50 Transparent region(s)-   60 Non-exposed and non-developed silver halide grains-   62 Silver metal particles-   64 Hydrophilic binder-   100 Conductive film element precursor provided-   105 Conductive film element precursor imagewise exposed-   107 Imagewise exposure of first side of conductive film element    precursor-   109 Imagewise exposure of second side of conductive film element    precursor-   110 Exposed conductive film element developed-   112 Development of first side of imagewise exposed precursor-   114 Development of second side of imagewise exposed precursor-   D1 Silver micro-wire maximum height-   D2 Silver micro-wire minimum height-   L Silver micro-wire length-   S1 Distance between adjacent silver main wires-   S2 Distance between adjacent silver micro-wires-   W Silver micro-wire width

The invention claimed is:
 1. An electrically-conductive articlecomprising a transparent substrate having a first supporting side and anopposing second supporting side, the first supporting side comprising:an electrically-conductive silver connector wire pattern, andoptionally, transparent regions outside of the electrically-conductivesilver connector wire pattern, wherein: (i) the electrically-conductivesilver connector wire pattern comprises at least one silver main wirethat comprises two or more silver micro-wires that are electricallyconnected to a silver end wire at an end of the at least one silver mainwire, the silver micro-wires and the silver end wire in the at least onesilver main wire forming a bundled pattern, each silver micro-wirehaving an average width of at least 0.5 μm and up to and including 10μm; (ii) the average length of each silver micro-wire is at least 1 mm;(iii) the ratio of the average width of each silver micro-wire to theaverage distance between any two adjacent silver micro-wires in eachbundled pattern is at least 0.5:1 but less than 2:1; and (iv) theelectrically-conductive silver connector wire pattern has an integratedtransmittance of less than 68%.
 2. The electrically-conductive articleof claim 1, wherein for each silver micro-wire, the ratio of maximumheight to minimum height is at least 1.1:1.
 3. Theelectrically-conductive article of claim 1, wherein the at least onesilver micro-wire has a maximum height that is its center height.
 4. Theelectrically-conductive article of claim 1, wherein the at least onesilver micro-wire has a maximum height that is closer to its outer edgethan to its center.
 5. The electrically-conductive article of claim 1,wherein each bundled pattern comprises at least one silver cross-wirebetween adjacent silver micro-wires that is not at the end of theadjacent silver micro-wires.
 6. The electrically-conductive article ofclaim 1, wherein the at least one silver main wire comprises from two toten silver micro-wires in a bundled pattern.
 7. Theelectrically-conductive article of claim 1, wherein the average distancebetween any at least two adjacent silver main wires is greater than theaverage distance between any two adjacent silver micro-wires in eachbundled pattern by at least 30%.
 8. The electrically-conductive articleof claim 1, wherein the ratio of the average width of each silvermicro-wire to the average distance between two adjacent silvermicro-wires in each bundled pattern is at least 1:1 and up to andincluding 2:1.
 9. The electrically-conductive article of claim 1,wherein the electrically-conductive silver connector wire pattern has anintegrated transmittance of less than 50%.
 10. A touch screen devicecomprising the electrically-conductive article of claim
 1. 11. Theelectrically-conductive article of claim 1, wherein theelectrically-conductive silver connector wire pattern comprises at leasttwo adjacent silver main wires, and the average distance between the atleast two adjacent silver main wires is greater than the averagedistance between any two adjacent silver micro-wires in each bundledpattern.
 12. The electrically-conductive article of claim 11, whereinthe average distance between any two adjacent silver micro-wires in eachbundled pattern is at least 2 μm and up to and including 10 μm.
 13. Theelectrically-conductive article of claim 1, wherein each bundled patterncomprises multiple silver cross-wires in a set of adjacent silvermicro-wires that are offset from multiple silver cross-wires in anotherset of adjacent silver micro-wires.
 14. The electrically-conductivearticle of claim 13, wherein each of the multiple silver cross-wires issubstantially perpendicular to the adjacent silver micro-wires.
 15. Theelectrically-conductive article of claim 1, further comprising on theopposing second supporting side of the transparent substrate: anopposing electrically-conductive silver connector wire pattern, andoptionally, (c) transparent regions outside of the opposingelectrically-conductive silver connector wire pattern, wherein, on theopposing second supporting side of the transparent substrate: (i) theopposing electrically-conductive silver connector wire pattern comprisesat least one silver main wire that comprises two or more silvermicro-wires that are electrically connected to a silver end wire at anend of the at least one silver main wire, the two or more silvermicro-wires and the silver end wire in the at least one silver main wireforming a bundled pattern, each silver micro-wire having an averagewidth of at least 0.5 μm and up to and including 10 μm; (ii) the averagelength of each silver micro-wire is at least 1 mm; (iii) the ratio ofthe average width of each silver micro-wire to the average distancebetween two adjacent silver micro-wires in each bundled pattern is atleast 0.5:1 but less than 2:1; and (iv) the opposingelectrically-conductive silver connector wire pattern has an integratedtransmittance of less than 68%.
 16. The electrically-conductive articleof claim 15, wherein the opposing electrically-conductive silverconnector wire pattern comprises at least two adjacent silver mainwires, and the average distance between these at least two adjacentsilver main wires is greater than the average distance between any twoadjacent silver micro-wires in each bundled pattern.
 17. Theelectrically-conductive article of claim 16, wherein the averagedistance between any two adjacent silver micro-wires in each bundledpattern on the opposing second supporting side of the transparentsubstrate is at least 2 μm and up to and including 10 μm.